In general, radio wave absorbers are arranged on the walls and ceilings of anechoic chambers in which product testing is performed on an electronic product or the like. Besides the radio wave absorbers in pyramid or conical shapes, examples include a sonic wave/radio having a radio absorption layer formed by making a conductive paint adhere to glass fiber in a mat shape with a sonic wave absorption layer laid thereover (see, for example, Patent Document 1). A λ/4 type radio wave absorber has been also known, which is formed by inserting a dielectric layer between a resistance film and a radio wave reflector for selectively absorbing a radio wave at a specified frequency (see, for example, Patent Document 2)    Patent Document 1: Japanese Unexamined Patent Application Publication 2003-86988    Patent Document 2: Japanese Unexamined Patent Application Publication 5-335832